I feel your pain StonedOwl, the only good rat is a dead rat.
Traps are the best option enough said on that, if you use poison then you need to change poisons every couple of months. I've seen my share of rat turds with chunks of green bait, they become immune to the chemical so you've got to change it up.
I was assigned a couple of Tysons hog farms out in the woods of NW Arkansa back in the mid 90's, one of the units was infested with rats, and I mean infested. Was inseminating a sow one morning and looked behind me and saw 18 eyeballs watching through a broken concrete block, it was game on after that.
It took a couple of months but it finally got under controll. Changed chemicals weekly, and we found some surprising ways of rodent control along the way here's a couple that work wonders and very safe if you have pets/children. Dr. Pepper, don't laugh, a rat can't burb and they rupture internally. Mortor mix, don't laugh, the stuff sets up in their gut and they are blocked. Mortor mix is high in salt and rats love the stuff.
Hope you get your rodent problem under control brother, if they ate my plants I would have no problem killing them or anything else for that matter.
jj